Supplementary Figure 2: T_FR cells regulate early GC responses.

a) Antibody responses in T_FR-DTR mice with pre-GC T_FR deletion strategies. T_FR-DTR mice were immunized with NP-OVA and received DT on days 5,7 and 9. Serum was collected on day 21 and NP-specific IgG (left), total IgA (middle) and total IgE (right) were measured. b) Phenotype of T_FR cells in T_FR-DTR mice with early (left) or pre-GC (right) start T_FR deletion strategies. T_FR-DTR mice were immunized with NP-OVA and received DT on days 2,4,6 (left) or 5,7 and 9 (right). Expression of CXCR5, ICOS, PD-1 or Ki67 was measured on day 7 (left) or day 21 (right). c) Assessment of B cell responses in T_FR-DTR mice with post-GC T_FR deletion strategies. T_FR-DTR mice were immunized with NP-OVA and received DT on days 10,12 and 14. Serum was collected on day 21 and NP-specific IgG (left), total IgA (middle) and total IgE (right) were measured. d) Expression of CXCR5, ICOS and Ki67 on T_FR cells in control or T_FR-DTR mice in post-GC deletion experiments. FoxP3^Cre Cxcr5^wt control or T_FR-DTR mice which were immunized with NP-OVA, given DT on days 10,12, and 14 and draining lymph nodes harvested on day 21. e) Evaluation of B cell responses early during pre-GC T_FR deletion strategies. T_FR-DTR mice were immunized with NP-OVA and received DT on days 5,7 and 9. Draining lymph nodes were collected on day 14 for the indicated analysis. T_FR (CD4⁺ICOS⁺CXCR5⁺FoxP3⁺CD19-) cells, GC B (CD19⁺GL7⁺FAS⁺) cells, Plasma cells (CD138⁺) and class switched B cells (CD19⁺GL7⁺IgG1⁺) cells were quantified. f) Evaluation of B cell responses late during post-GC T_FR deletion strategies. T_FR-DTR mice were immunized with NP-OVA and received DT on days 10,12 and 14. Draining lymph nodes and serum was collected on day 26 for analysis. GC B (CD19⁺GL7⁺FAS⁺) cells from lymph nodes, NP specific IgG from serum, and total IgG from serum were quantified. Column graphs represent the mean with error bars indicating standard error. P value indicates two-tailed student’s T test. Data are from an individual experiments and are representative of two experimental repeats.